Gyroscope



Jan. 30, 1968 s ET AL 3,365,960

GYROSCOPE Filed April 16, 1965 '5 Sheets-Sheet 1 INVENTORS ELLIOTT J. SIFF IRVING SCHAFFER ATTORN EYS.

Jan. 30, 1968 E. J. SfFF ET AL 3,365,960-

GYROSCOPE Filed April 16, 1965 5 Sheets-Sheet 2 A FIG. 2

INVENTORS ELLIOTT J'. SIFF IRVING SHAFFER ATTORNEYS Jan. 30, 1968 5.15m: ET AL 3,365,960

GYROSCOPE Filed April 16, 1965 5 Sheets-Sheet C5 INVENTORS ELLIOTT J'. SIFF Kw, W, M, 1 4; M

ATTORNEYS IRVING SCHAFFER Jan. 30, 1968 E. .1. SIFF ET AL 3,365,960

GYROSCOPE I Filed April 16, 1965 5 Sheets-Sheet 4 FIG. 7

INVENTORS ELLIOTT J. SIFF ATTORNEYS Jan. 30, 1968 Filed April 16, 1965 E. J. SIFF ET GYROSCOPE 5 Sheets-Sheet 5 FIG. IO

FIG. I I

INVENTORS ELLIOTT d. SIFF BY IRVING KSEIEFER I 2&.4,MA1, ,4 9/1 4 ATTORNEYS United States Patent 3,365,960 GYROSCOPE Elliott J. Sift, Bridgeport, and Irving Schalfer, Fairfield,

Conn., assignors to American Chain & Cable Comgxxany, Inc., New York, N.Y., a corporation of New ork Continuation-impart of application Ser. No. 365,669,

May 7, 1964. This application Apr. 16, 1965, Ser.

28 Claims. (Cl. 74--5.4)

This is a continuation-in-part of application Ser. No. 365,669, filed May 7, 1964, and now abandoned.

This invention relates to gyroscopes, especially of the type adapted to be miniaturized for guidance systems and the like and, more particularly, to rate gyros designed to simplify and reduce the number of component parts and to render them more reliable in function.

Considerable attention has been given to the design of small gyroscopes for guidance control of high speed aircraft and space vehicles but few concepts of a fundamentally different nature from those of traditional gyro design have been put forward to solve the special problems of these new applications. The art of subminiature gyros is still left with demanding tolerance requirements in locating the rotor and spin motor concentrically within an inner container which must then be located and sup ported concentrically within the outer housing. Also, rate gyros which have been simplified by removal of the outer gimbal rings have the plane of precession displaced from the center of mass of the rotor, causing an inertial imbalance in the system. The design of pick-off meansin rate gyros of a conventional type is equally derivative inasmuch as the microsyn type assembly remains the principal form available, With all its demanding tolerances for maintaining accurate concentricities between armature and stator mounted on separate pieces. In addition the old El assembly commonly used in transducers and some gyros suffers from erroneous signals caused by armature to stator misalignment both under static and dynamic environments.

These and other approaches to rate gyro design have been departed from to great advantage in the present invention. Broadly stated, gyros according to our concepts comprise a sealed outer casing and a supporting member fixed in the casing. A support shaft is cantilevered from the supporting member within the outer casing. This support shaft has an inner portion which is affixed to the supporting member, and an outer end portion which defines the gyro spin axis. The shaft outer end portion is movable relative to the shaft inner end portion on a single precession axis at right angle to the spin axis but is restrained against movement on all other axes relative thereto. A rotor rotatable about the spin axis is balanced at the intersection of the precession and spin axes. Means are inciuded for rotating this rotor. On the extremity of the movable shaft end portion is a pick-off armature bar which is perpendicular to the precession and spin axes. Coil wound core means are opposed to one another on opposite sides of the bar for establishing a field through which the bar moves to produce a signal when the rotor precesses the shaft outer end portion. Mounting means on the casing separately and adjustably support each core means for null adjustment of the signal. Movably mounted in the field between the core means is magnetically permeable adjustment means for varying the field during fine null adjustment of the signal.

Advantageously the support shaft of the new gyro is formed with a flat necked portion intermediateits inner and outer end portion, the 'flexure axis of said fiat necked portion defining the precession axis of the gyro.

It is contemplated that these and additional elements 3,365,960 Patented Jan. 30, 1968 be combined in the invention and also that certain su bcombinations of the elements stand alone in other environments. Among the latter are the balanced rotor on the supporting shaft adapted to precess only about one axis, the pick-off armature bar and its associated coil wound core means, the initial adjustability of the mounting means for the pick-off cores and the means for varying the pick-off core field during fine null adjustment.

In the new gyro the rotor assembly (including its housing) can be moved along the outer portion of the support shaft to balance the gyro precisely as required. The integral flat necked spin shaft poses no problem of eccentricity in its manufacture and it is particularly resistant to shock and vibration because strains on the neck are well reinforced against in all directions except the one desired for precession. In addition the pick-off system is so constructed as to be essentially insensitive to axial twisting forces or bending forces not about the precession axis.

A prefered embodiment of the invention is described below wit-h reference to the accompanying drawings, wherein:

FIG. 1 is a longitudinal section taken through the center line of the gyro;

FIG. 2 is an enlarged fragmentary section taken along the line .22 of FIG. 1;

FIG. 3 is an enlarged fragmentary section taken along 3-3 of FIG. 5;

FIG. 4 is an enlarged fragmentary section taken along the line 4-4 of FIG. 5;

FIG. 5 is a section taken along the line 55 of FIG.

FIG. 6 is an end elevation partly broken away as viewed from the right in FIG. 1;

FIG. 7 is a fragmentary longitudinal section similar to FIG. I particularly illustrating the torquer means;

FIG. 8 illustrates the elements comprising the torquer means shown in FIG. 7;

FIG. 9 is a fragmentary longitudinal section of the double pick-off embodiment;

FIG. 10 is a schematic illustrating modified coil windings of the pick-off means; and

FIG. 11 is a'partial section of another embodiment of the pick-off means illustrating the gyros function as a rate switch.

In this embodiment of the new rate gyro a substantially cylindrical outer casing 10, which may be only about an inch and a half long and about one inch in diameter, is sealed at one end by an annular plate 11, formed with a central aperture 11', a bellows 12 and a bellows closure plate 12'. The opposite end of the casing 10 is closed by a cover plate 13, as shown in FIG. 1. All voids within the outer casing are completely filled by a damping liquid of predetermined viscosity, with the exception of one hollow subassembly within the outer casing. The damping liquid is introduced within the outer casing through an aperture in the cover plate 13 closed by a removable plug 14. The outer surface of the bellows 12 contains the damping liquid and its inner surface is exposed to atmospheric pressure through the central aperture 11 in the plate 11, so that thermal expansion and contraction of the liquid mass within the outer casing produces contraction and expansion of the bellows 12 Without significant change in the pressure on the fluid. Also, the spring force of the bellows exerts a positive force on the liquid mass to prevent the formation of voids in the fluid.

At the end portion of the casing 10 adjacent to the bellows 12 is mounted a supporting member 15 formed with a pair of holes 16 and 17 through which the damping liquid may pass. The supporting member 15 is a relatively heavy disc from the center of which a support shaft 18 is cantilevered toward the opposite cover plate 13 along the outer casing axis. The support shaft 18 includes a first relatively small diameter portion 19 affixed with respect to the supporting member and the outer casing 10, a flexible intermediate flat necked portion 21, and a relatively large diameter end portion 22 which is tiltable on a single precession axis defined by the flexure axis of the shaft occurs about the flexure axis extending diametrically through the shaft at the narrowest part .of the flat necked portion 21. This flexure axis is the precession axis Y of the gyro shown in FIG. 2. Only those bending moment forces acting about the precession axis will cause movement of the outer end portion 22 of the shaft 18, and ordinary torsional forces or other bending moments exerted will produce no measurable strain in the contemplated operation of the gyro.

Aflixed coaxially on the relatively large diameter outer end portion of the support shaft is a sealed annular container 24 defined by a cylindrical body 25, an end wall 26 adjacent to the supporting member 15, an inner sleeve 27, and an end wall 28. The container 24 and its contents are wholly supported on the outer end portion 22 of the support shaft by atfixing of the sleeve 27 thereto. A first bearing assembly comprising an inner race 30, an outer race 31 and bearing balls 32 is mounted about the sleeve 27. Spaced axially from this bearing assembly by inner and outer spacing rings 34 and 35 is a second bearing assembly comprising inner and outer races 37 and 38 and bearing balls 40. A nut 41 threaded about the end of the sleeve 27 holds the inner races and 37 and the inner spacing ring 34 in place. An externally threaded ring 42 which is mounted as mentioned below holds the outer races 31 and 38 and the outer spacing ring in place.

It was mentioned previously that all voids within the outer casing 10 are filled with the damping liquid except for one, and that one is within the container 24. An increase in the temperature of this damping liquid reduces its viscosity and permits easier movement of the container 24 and the outer shaft end portion 22 about the flat necked portion 21 of the shaft. Conversely, these elements encounter more resistance from the damping liquid when its viscosity increases as a result of a drop in temperature. Effective control on these variables may be achieved by defining a narrow annular gap 44 between an annulus 45 on the container 24 and an opposed portion 46 of the supporting member 15. By making the annulus 45 of a material which expands and contracts to a known greater degree than the supporting member 15, the gap 44 is narrowed at higher temperatures and widened at lower temperatures. Thus, the damping liquid within the gap 44 resists motion of the annulus 45 to a greater degree at higher temperatures when the liquid is less viscous and to a lesser degree at lower temperature when the liquid is more viscous. This in turn influences movement of the container 24 and the outer movable shaft portion 22 about the precession axis in the flat necked shaft portion 21 in a manner which eliminates the variable effect on the motion of those parts with changes in the viscosity of the damping liquid. It is preferable to form the annulus 45 of nylon because of its marked coefficient of thermal expansion. Also, the gap 44 is advantageously defined by surfaces on the annulus 45 and the supporting member 15 which are spherically curved on a radius centered at the intersection of the precession and spin axes within the flat necked shaft portion 21.

Within the container 24 is a rotor 48 and energizing stator 49. The rotor is fixed concentrically about the outer bearing races 31 and 38 and the outer spacing ring 35 coaxially with respect to the outer shaft end portion 22. The ring 42 mentioned previously is threaded within the shoulder of the rotor 48 to hold the outer bearing races 31 and 38 and spacing ring 35 in place.

One of the major features of the invention is that the precession elements consisting of the container 24, the rotor-stator assembly within it, and the movable shaft end portion 22 are balanced about a point coinciding with the intersection of the precession and spin axes within the flat necked shaft portion 21. This balance may be achieved by sliding the container 24 along the movable shaft end portion 22 so that the combined center of gravity of the precession elements are at the desired location. As long as the precession elements are balanced at the single point of suspension Where the precession and spin axes intersect, the container 24 does not require precise dimensional tolerances placing it concentrically within the outer casing 10. It should also be noted that there is little difficulty involved in machining the support shaft 18 so that its outer end portion 22 is larger than but accurately concentric with the shaft portion 19 fixed to the supporting member 15. Consequently very little alignment control is required during assembly of the gyro.

The rotor 48 is configured to fit around the stator assembly 49, which comprises a plurality of stator arms 50 and coils 51 of a synchronous electric motor supported on a flanged bushing 53 concentrically mounted on the sleeve 27 adjacent to the end cover 28 of the container 24. A hysteresis ring 54 is fixed to the rotor 48 in circumferential opposition to the stator assembly. As shown in FIGS. 1, 3 and 5, three electrical pins 55, 56 and 57 extend in sealed relation through the end cover 28 of the container 24 from the terminals of the synchronous motor alongside the wall of the outer casing 10. The outer ends of these pins 55, 56 and 57 are connected respectively by flexible pigtail conductors 59, 60 and 61 to respective terminal posts 63, 64 and 65 mounted within the outer casing 10. The pigtail connections 59, 60 and 61 are designed to present negligible resistance to the free motion of the container 24 as it precesses on the shaft outer end portion 22 about the flat necked shaft portion 21.

When the rotor 48 precesses during operation it may displace the container 24 angularly at a maximum of about three degrees in either direction about the fiat necked shaft portion 21. The inner walls of the outer casing 10 or the inner end portion 19 of the support shaft provides a stop for limiting this angular motion of the container so as not to exceed the elastic limit of the flat necked shaft portion 21 thus assuring that the elasticity of the latter may be relied upon to restore the container and the movable shaft end portion 22 to their nominal rest or null position. If desired, a torquer may also be provided for augmenting the elastic restoring force of the 'flat necked portion 21 by mounting a permanent magnet ring concentrically within the annulus 45 on the container in opposition to an electromagnetic coil on the supporting element 15.

Referring to FIGS. 1, 3, 4 and 5, unique pick-off means are provided to translate the precession of the container 24 into an electrical signal. This includes a rectangular elongated armature bar 67 of magnetic material mounted on the extremity of the support shaft outer end portion 22 perpendicular to the precession and spin axes. On each opposite side of the bar 67 is one of a pair of coplanar substantially E-shaped cores 69 and 70, the former having a center leg 71 and outside legs 72 and 73 and the latter having a center leg 74 and outside legs 75 and 76. The legs of the cores 69 and are in end-to-end opposition and the two center legs 71 and 74 carry respective primary coils 77 and 78. The opposed pairs of outside legs 72 and carry respective secondary coils 79 and 80 of the same polarity. The other opposed pair of outside legs 73 and 76 carry respective secondary coils 81 and 82 of the same polarity opposite to that of the secondary coils 79 and 80.

When the rotor 48 precesses the tiltable shaft outer end portion 22, the armature bar 67 passes through the magnetic field between the cores 69 and 70 and produces an unbalanced signal in the secondary coils. This precession movement of the piclooff armature 67 is up and down as seen in FIGS. 1 and 5. The secondary coils 79 and 80 reinforce each other as do the secondary coils 81 and 82, so that the displacement of the armature 67 through a given distance produces an output which is double that when a single E-shaped core is employed. This pick-off system is not affected by and does not give a false signal on account of any slight axial twist which might occur in the armature bar 67 during its precession, because one end of the bar would, for example, approach the secondary coil 79 and increase its output while the other end of the bar 67 would approach the diagonally opposite secondary coil 82 and increase its output, thus cancelling the twisting error output signal. If the armature bar 67 were to move laterally from side-to-side, there would be similar balanced decrease and increase in coil outputs which would cancel out to balance the net signal.

It should be noted here that by changing the coil windings of the pick-off means that a large signal output can be generated from a very small lateral movement of the armature. Such a modified winding is shown schematically in FIG. 10.

In this embodiment the coils S0 and 82 are of the same polarity. The coils 79 and 81 are of the same polarity with each other but opposite to the polarity of coils 80 and 82.

Referring to FIG. 10, the armature 67 is oriented parallel to the precession axis and perpendicular to the spin axis so that it can move to the up or down only. It can be seen that precession of the gyro will cause the armature to move laterally rather than along its longitudinal axis as heretofore described. The area available for such movement is indeed limited. However. it has been found that small precession movements are easily detected. The reason for this is that a small movement of the relatively large mass of the armature 67 permits a great increase in the magnetic flux to the secondary coils on one of the E-shaped cores while decreasing the flux at the secondary coils of the other core. Since the secondary coil windings on a given E-shaped core are the same, the potential output of the secondary coil on one outside leg is augmented by the potential output of the coil on the other outside leg.

Bosses 85 and 86 extending from the inner wall of the outer casing diagonally opposite one another provide support for the respective E-shaped cores 69 and 70. Each of the cores 69 and 70 snaps into respective resilient clips 89. In assembly, the clips 89 may be secured to the bosses 85 and 86 by respective grommets 90. Epoxy glue may be disposed on the back leg 91, 91' of each or the cores 69 and 70 before they are snapped into the clips. While the glue is drying, the position of the cores 69 and 70 may be adjusted by sliding them perpendicular to the spin axis so that a null signal is produced in the secondary coils of the pick-off system when the pickoff armature bar 67 is in its rest or null position.

Flexible printed circuitry 92 provides for interconnecting the secondary coils and for connecting both primary and secondary coils and motor leads to external terminal posts 93 extending through the cover plate 13 where they are accessible at the exterior of the gyro assembly. The printed circuit 92 is of conventional construction, comprising foil conductors 94 sandwiched between thin layers of flexible polytetrafluoroethylene or other appropriate plastic sheet material 95. The printed circuit element is configured to form an annular section 96 which fits against the inside face of the cover plate 13 and through which connections are made to the terminal posts 93. This annular section is connected by an intermediate accordianpleated neck section 97 to a generally rectangular section 98 and to laterally extending arm sections 100. The latter extend about the inside periphery of the casing 10 and include tabs 101 through which connections are made to the motor terminal posts 63, 64 and 65. The rectangular section overlies the E-shaped cores, and includes tabs 102 which are bent downwardly and connected to pins 103 on terminal boards 104 overlying the primary and secondary coils. The leads from these coils are brought out and secured to the pins 103 on the terminal boards, to provide mechanically strong anchorages for the electrical connections.

The flexible printed circuit sheet can readily be mounted in position for making electrical connections to the motor and coil terminals with the cover plate 13 removed, and its annular section can likewise be mounted on the inside surface of the cover plate and connected to the terminal posts 93 while the cover plate is removed; and then by virtue of the flexibility of the accordian-pleated neck section, the cover can be swung over and mounted on the casing without disturbing the electrical connections.

Within the array of terminal posts on the cover plate and held against the inside face thereof by a pair of screws 105 is a magnetically permeable null adjustment bar 106. The holes 107 through which the screws extend are oversize, so that by loosening the screws slightly, the bar 106 may be shifted to vary the field between the E-shaped cores. During fine null adjustment of the pick-01f system, the screws 105 are loosened and the bar 106 shifted by manipulation of the screws to produce an accurate null signal when the gyro is subjected to no precession force. The screws are then tightened to lock the bar 106 in place.

A cup shaped housing 108 hermetically sealed to the cover plate 13 extends through the annular portion of the printed circuit sheet and through another opening in the rectangular section thereof which overlies the E-cores. This housing insures against leakage of damping fluid through the screw holes 107. A removable cover 110 is mounted over the screws 105 and the plug 14 after the gyro assembly has been filled with damping fluid.

Another embodiment of the invention is illustrated in FIG. 9 which is for a double pick-olf gyro. The double pick-off embodiment is a compound gyro substantially comprising two axially aligned gyros of the type described herein with, however, the precession axes being mutually perpendicular. Thus, the double pick-off gyro of this compact design is capable of generating independent signals responsive to precession about two axes.

Referring to FIG. 9, and, for convenience, using the same identifying numbers as used heretofore with, however, a prime indication to designate the corresponding part in one-half of the gyro assembly, the support shaft 18 includes a relatively small diameter inner portion 19 which is common to both halves of the gyroscope assembly. The relatively small diameter portion 19 is fixed with respect to supporting members 15 which in turn are fixed to the outer casing 10 at points inward of the casing ends. The support shaft 18 includes flexible flat necked portions 21 and 21' intermediate the inner portion 19 and the large diameter outer end portions 22 and 22'. Thus, the support shaft 18 is effectively cantilevered in opposite directions from the support members 15 and its axis defines the spin axis of both the outer end portions 22 and 22.

Each outer end portion 22 and. 22' is tiltable relative to the inner portion 19 and on a. single precession axis defined by the flexure axis of the hat necked portions 21 and 21 respectively. The flexure axis of the flat necked portion 21 is perpendicular to the spin axis and to the flexure axis of the flat necked portion 21. Thus, the precession axes are perpendicular to each other.

Sealed annular containers 24 and 24' are afiixed to the relatively larger diameter end portions 22 and 22' respectively. The containers 24 and 24 enclose the rotors, sleeves, bearings, stators and other elements identical to those described with respect to the single gyro of FIG. 1. However, these enclosed parts are not specifically shown in FIG. 9.

Outward of the containers 24 and 24 are the pick-off means denoted generally as 112 and 112'. Each comprises in part an elongated armature bar 67 and 67' respectively. Each armature bar 67 and 67 is mounted upon respective shaft ends 22 and 22 and perpendicular to the respective precession and spin axes. Thus, the armature bars 67 and 67' are perpendicular to each other. In all other respects, except of course for orientation, the pick-off means 112 and 112' comprise the same elements as heretofore described as making up the pick-off means for the single gyro.

It can be seen that each shaft end portion 22 and 22 supports a number of elements, including a rotor, a stator and the container for both, as well as an armature. While the armature is an element of the pick-off assembly, it is also an element of what shall be referred to collectively as the precession unit; namely, that unit whose elements, taken together, are supported by and move with a shaft end portion. Each precession unit is balanced about the intersection of its respective precession on spin axis.

In the double pick-off gyro embodiment a bellows 114 is provided of somewhat different construction than shown in the single gyro assembly. The bellows 114 is substantially in the form of an annulus, the inner wall of the bellows defining an axial opening for the relatively small diameter inner portion 19 of the support shaft 18 to pass therethrough. The bellows is sealed and evacuated. Its normal position in the atmosphere is fully compressed. The gyro is filled hot and sealed, the bellows expanding as the gyro cools.

Where the gyro of the invention is to perform the function of a rate switch in either the single or double embodiments, the E-shaped cores and their attendant windings of the pick-off assembly may be eliminated and contact points substituted. This embodiment, shown in FIG. 11, comprises micro-switches 118 which when contacted by a bar 122 afiixed to the shaft end 22, close a circuit which signals a predetermined degree of precession.

As noted above, a torquer may also be provided for augmenting the elastic restoring force of the fiat necked portion 21. Further, a torquer means may be provided in an embodiment of the invention where the novel damping means discussed above is not utilized. Such a torquer may serve as a damping means as well as a means for checking gyro readings.

Referring to FIG. 7 there is shown an embodiment of the invention having a torquer means 200. The torquer means 200 comprises an annular magnetically permeable return path ring 202 secured to the container 24 at a position comparable to the placement of the annulus 45 seen in FIG. 1. Fixed to the return path ring 202 are two permanent magnets 204 and 206. These magnets are in diametrically opposed positions on the ring 202 and further oriented so that their opposite poles are adjacent the ring. Thus, as illustrated in FIG. 80, permanent magnet 204 has its south pole adjacent the ring 202 and the permanent magnet 206 has its north pole adjacent the ring. The magnets 204 and 206 are, additionally, located on a line perpendicular to the fiexure axis of the flat necked portion 21.

In opposition to the magnets 204 and 206 and to the ring 202 is an electromagnetic coil 208 on the supporting element 15. The electromagnetic coil 208 in turn comprises a magnetically permeable ring 210 and windings 212.

When the coil 208 is energized a magnetic field is established which acts upon the permanent magnets 204 and 206. Because the magnets 204 and 206 have opposite poles facing the electromagnetic coil 208 a torque is applied to the container 24 tending to tilt it about the fiexure axis of flat necked portion 21. The degree of tilting is dependent upon the strength and polarity of the magnetic field created when the electromagnetic coil 208 is energized.

The torquer means so described may advantageously serve several functions. It may be used for checking the output signal of the pick-off means. Thus, the electromagnetic coil 208 may be energized a known amount to cause the container 24 to tilt to a predetermined degree. The signal from the pick-off means may then be checked to see if it matches with the predetermined value.

The torquer means 200 may also function as a damper. For such purpose the signal from the pick-off means is advantageously utilized to energize the electromagnetic coil 208 in response to the direction and degree of precession. Accordingly, the electrical signal from the pickoff assembly is suitably amplified by amplifier means and directed through the coil 208 to establish a magnetic field the polarity and strength of which corresponds to the direction and strength of the net signal from the pickoff. The torque thus applied acts to dampen the movement of the container 24.

A further refinement of this technique is to use the torquer 200 to substantially restrain the container 24 against any precession and to take the measure of the current necessary to prevent precession as the gyros output signal. Thus, the signal from the pick-off assembly may be amplified by amplifier means to such an extent that the torquing forces will offset the precession forces tending to tilt the container 24. The degree of amplification required to maintain the container 24 and thus the rotor assembly in a balanced condition about the gyro spin axis will then be a measure of gyro precession or, more accurately, the imaginary precession of the gyro.

We claim:

1. A gyro assembly comprising:

(a) a sealed outer casing,

(b) a supporting member fixed in said outer casing,

(c) a support shaft cantilevered from said supporting member Within the casing, said shaft having an inner end portion attached to said supporting member and an outer end portion defining a spin axis and movable relative to said inner end portion on a single precession axis disposed at a right angle to said spin axis but restrained against movement relative thereto on other axes,

(d) a rotor rotatable about said spin axis supported on said shaft outer end portion,

(e) means for rotating said rotor,

(f) a pick-off armature bar on the extremity of the movable shaft end portion perpendicular to said precession and spin axes,

( 1) said shaft outer end portion and the elements supported thereby constituting gyro precession elements movable about said precession axis, said precession elements being balanced about the intersection of the precession and spin axes,

(g) coil-wound core means opposed to one another on opposite sides of said armature bar for establishing a field through which said bar moves to produce a signal when said precession elements precess,

(h) mounting means on said casing supporting each core means and permitting initial null adjustment of the signal, and

(i) magnetically permeable adjustment means movably mounted in the field between the core means for varying said field during fine null adjustment of the signal.

2. A gyro assembly according to claim 1 wherein the support shaft is formed with a flat necked portion intermediate its inner and outer end portions, the fiexure axis of said flat necked portion defining the precession axis of the gyro.

3. A gyro assembly according to claim 1 wherein said casing is substantially cylindrical and said support shaft and spin axis is cantilevered along the casing axis.

4. A gyro assembly according to claim 1 wherein said core means comprises a pair of coplanar substantially E-shaped cores having their respective legs facing one another end-to-end.

5. A gyro assembly according to claim 4 wherein said magnetically permeable adjustment means comprises a member of magnetic material disposed between the E- shaped cores and to one side thereof.

6. A gyro assembly according to claim 1 which includes a sealed container fixed coaxially on saidmovable shaft end portion and enclosing said rotor and said means for rotating said rotor, and a damping liquid filling all voids in said casing except that within said container.

7. A gyro assembly according to claim 6 which includes damping control means on said container defining a gap with respect to and differing predeterminedly in thermal expansibility from an opposed portion of said supporting element.

8. A gyro assembly according to claim 6 which includes bellows means exposed to atmosphere on one side and containing said liquid on its opposite side.

9. A gyro comprising:

(a) a substantially cylindrical casing sealed at both ends,

(b) a supporting member fixed in said casing adjacent one end thereof,

() a support shaft defining a spin axis cantilevered from said supporting member toward the opposite end of the casing along the casing axis and having an outer end portion movable on a flexible intermediate flat necked portion about a single precession axis,

((1) a sealed annular container fixed coaxially on said shaft outer end portion,

(e) a damping liquid filling all voids in said outer casing except that within said container,

(f) damping control means on said container defining a gap with respect to and differing predeterminedly in thermal expansibility from an opposed portion of said supporting element,

(g) bellows means exposed to atmosphere on one side and containing said liquid on its opposite side,

(h) a rotor in said container rotatable about said shaft,

said rotor and container being balanced at the intersection of the precession and spin axes,

(i) synchronous electric motor means in said container for rotating said rotor,

(j) a pick-off armature bar on the extremity of the shaft outer end portion mounted perpendicular to said precession and spin axes,

(k) a pair of coplanar substantially E-shaped coilwound cores having their respective legs facing one another end-to-end on opposite sides of said bar for establishing a field through which said bar moves from a null position to produce a signal when said rotor precesses the movable outer end portion of the support shaft,

(1) mounting means on said casing separately supporting each E-shaped core and permitting initial adjustment of their positions for null adjustment of the signal, and

(m) magnetically permeable adjustment means disposed between the E-shaped cores to one side thereof and movable from the exterior of the casing for varying said field during fine null adjustment of the sig nal.

10. in a gyro including a rotor within a casing, a support shaft for supporting said rotor, said shaft having an inner shaft portion fixed with respect to and cantilevered within said casing and an outer end portion defining the gyro spin axis and supporting said rotor, and resiliently flexible means interconnecting the inner and outer end portions of said shaft permitting movement of the outer end portion relative to the inner portion only about a single precession axis.

11. The gyro according to claim 10 wherein the interconnecting means of the support shaft is a flat necked portion intermediate its inner and outer portions, the fiexure axis of said flat necked portion defining the single precession axis.

12. A gyro according to claim 10 wherein said shaft outer portion and elements carried thereby are balanced at the intersection of the precession and spin axes.

13. In a gyro including a rotor rotatable about a spin axis and angularly movable about a precession axis, and a pick-off armature bar mounted perpendicular to said precession and spin axes to precess with said rotor, coil wound core means for establishing a field through which said bar precesses to produce a signal comprising a pair of coplanar substantially E-shaped cores having their respective legs facing one another end-to-end on opposite sides of said bar.

14. A gyro according to claim 13 wherein the opposed center legs of the two E-shaped cores carry respective primary coils, one opposed pair of outside legs of the two Eashaped cores carries respective secondary coils of the same polarity, and the other opposed pair of outside legs of the two E-shaped cores carries respective secondary coils of the same polarity opposite to that of the firstmentioned secondary coils.

15. In a gyro including a cylindrical outer casing having therein a transverse member, a cylindrical rotor container coaxially mounted within said outer casing, a rotor mounted within said container for rotation on a spin axis coaxial with said casing and container axes, said container being tiltable on a precession axis perpendicular to said spin axis, and damping fluid filling the outer casing about the rotor container, means for damping the precession movement of the rotor container comprising a damping ring secured to one end of the rotor container and received in a groove formed in the transverse member of the outer casing, opposed surfaces of said ring and groove being closely spaced and being substantially spherically configured about a center at the intersection of the spin and precession axes of the gyro.

16. A gyro assembly comprising:

(a) a sealed outer casing,

(b) a supporting member fixed in said outer casing in termediate of the ends of the casing,

(c) a support shaft having (i) an inner portion secured to the supporting member, and

(ii) outer end portions cantilevered from the sup porting member and defining a spin axis,

(iii) each outer end portion movable relative to the inner portion about a single precession axis only, each precession axis being perpendicular to the spin axis,

(d) a rotor rotatably supported on each shaft outer end portion and rotatable about the spin axis,

(e) means for rotating the rotors,

(f) a pick-off armature bar on the extremity of each movable shaft end portion perpendicular to the spin axis and to its respective precession axis, each shaft end portion and the elements supported thereby constituting a precession unit movable about its respective precession axis, each precession unit being balanced about the intersection of its respective precession and spin axes,

(g) coil-wound core means opposed to one another on opposite sides of each armature bar for establishing fields through which the armature bars move to produce signals when each precession unit precesses.

17. A gyro assembly according to claim 16 wherein the support shaft is formed with two flat necked portions, one flat necked portion intermediate the inner portion and one outer end portion and the other flat necked portion intermediate the inner portion and the other end portion, the fiexure axis of each flat necked portion being per- 11 pendicular to the other end each defining a precession axis.

18. A gyro assembly according to claim 17 having in addition:

(a) mounting means on the casing supporting each core means and permitting initial null adjustment of the Signals, and

(b) magnetically permeable adjustment means movably mounted in the fields between the core means for varying the field during fine null adjustment of the signals.

19. A gyro assembly according to claim 18 wherein the core means opposed to one another on opposite sides of each armature bar comprises a pair of coplanar substantially E-shaped cores having their respective legs facing one another end-to-end.

20. A gyro assembly according to claim 19 having in addition a sealed container fixed coaxially on each movable shaft end portion and enclosing one rotor and means for rotating said rotor, and a damping liquid filling the voids in the casing except that void within each container.

21. A gyro assembly according to claim 1 which includes (a) a sealed container fixed coaxially on the movable shaft end portion enclosing the rotor and the means for rotating the rotor, and

(b) a torquer means comprising (i) an annular magnetically permeable ring secured to the container,

(ii) two permanent magnets fixed to the ring in diametrically opposed positions thereon and having their opposite poles adjacent the ring, and

(iii) an electromagnetic coil upon the supporting element.

22. A gyro assembly according to claim 21 wherein the two permanent magnets are disposed on a line substantially at right angles to the precession axis.

23. A gyro assembly according to claim 22 wherein the annular magnetically permeable ring is secured to the inner end of the container and the electromagnetic coil upon the supporting element is in opposed relationship with the annular ring.

24. A gyro assembly according to claim 21 wherein the electromagnetic coil is electrically connected to the coilwound means for varying the magnetic field generated by the electromagnetic coil in accordance with the signal produced when the precession elements precess.

25. A gyro comprising:

(a) a sealed outer casing,

(b) a supporting member fixed in said casing,

(c) a support shaft defining a spin axis cantilevered from said supporting members within the casing, said shaft having an inner end portion attached to said supporting member and an outer end portion movable relative to said inner end portion on a single precession axis disposed at a right angle to said spin axis but restrained against movement relative thereto on other axes,

(d) a rotor rotatable about said spin axis supported on said shaft outer end portion,

(e) means in said container for rotating said rotor,

(f) a bar on the extremity of the shaft outer end portion mounted perpendicular to said precession and spin axes, and

(g) switch means mounted upon said casing and actuated by contact with said bar to produce a signal when the rotor precesses the movable outer portion of the support shaft to a predetermined degree.

26. In a gyro including a rotor rotatable about a spin axis and angularly movable about a precession axis, pickoff means comprising a pick-off armature bar mounted parallel to said precession axis and perpendicular to the spin axis to precess with said rotor, and coil wound core means opposed to one another on opposite sides of said bar for establishing a field through which said bar precesses to produce a signal.

27. A gyro according to claim 26 wherein said core means comprises a pair of coplanar substantially E-shaped cores having their respective legs facing one another end-to-end.

28. A gyro according to claim 27 wherein the opposed center legs of the two E-shaped cores carry respective primary coils, the outside legs of the one E-shaped core carries secondary coils of the same polarity, and the outside legs of the other E-shaped core carries secondary coils of the same polarity opposite to that of the firstmentioned secondary coils.

References Cited UNITED STATES PATENTS 2,407,657 9/1946 Esval 745.6 2,421,247 5/1947 Davis 745 2,817,240 12/1957 Sanders 745.6 2,829,521 4/1958 Kuipers 74'5.5 2,955,473 10/ 1960 Braumiller 74-5 .5 3,208,288 9/1965 Cohen 745.6 3,222,937 12/1965 Konet 745.5 3,251,233 5/1966 Duncan et al 74--5.4

FRED C. MATTERN, JR., Primary Examiner.

P. W. SULLIVAN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,365,960 January 30, 1968 Elliott J. Siff et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 2, line 26, after "along" insert the line column 5, line 39, for However." read However, column 10, line 1, for "The" read A column 11, line 1, for "end" read -"and Signed and sealed this 10th day of June 1969.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents 

1. A GYRO ASSEMBLY COMPRISING: (A) A SEALED OUTER CASING, (B) A SUPPORTING MEMBER FIXED IN SAID OUTER CASING, (C) A SUPPORT SHAFT CANTILEVERED FROM SAID SUPPORTING MEMBER WITHIN THE CASING, SAID SHAFT HAVING AN INNER END PORTION ATTACHED TO SAID SUPPORTING MEMBER AND AN OUTER END PORTION DEFINING A SPIN AXIS AND MOVABLE RELATIVE TO SAID INNER END PORTION ON A SINGLE PRECESSION AXIS DISPOSED AT A RIGHT ANGLE TO SAID SPIN AXIS BUT RESTRAINED AGAINST MOVEMENT RELATIVE THERETO ON OTHER AXES, (D) A ROTOR ROTATABLE ABOUT SAID SPIN AXIS SUPPORTED ON SAID SHAFT OUTER END PORTION, (E) MEANS FOR ROTATING SAID ROTOR, (F) A PICK-OFF ARMATURE BAR ON THE EXTREMITY OF THE MOVABLE SHAFT END PORTION PERPENDICULAR TO SAID PRECESSION AND SPIN AXES, (1) SAID SHAFT OUTER END PORTION AND THE ELEMENTS SUPPORTED THEREBY CONSTITUTING GYRO PRECESSION ELEMENTS MOVABLE ABOUT SAID PRECESSION AXIS, SAID PRECESSION ELEMENTS BEING BALANCED ABOUT THE INTERSECTION OF THE PRECESSION AND SPIN AXES, (G) COIL-WOUND CORE MEANS OPPOSED TO ONE ANOTHER ON OPPOSITE SIDES OF SAID ARMATURE BAR FOR ESTABLISHING A FIELD THROUGH WHICH SAID BAR MOVES TO PRODUCE A SIGNAL WHEN SAID PRECESSION ELEMENTS PRECESS, (H) MOUNTING MEANS ON SAID CASING SUPPORTING EACH CORE MEANS AND PERMITTING INITIAL NULL ADJUSTMENT OF THE SIGNAL, AND (I) MAGNETICALLY PERMEABLE ADJUSTMENT MEANS MOVABLY MOUNTED IN THE FIELD BETWEEN THE CORE MEANS FOR VARYING SAID FIELD DURING THE NULL ADJUSTMENT OF THE SIGNAL. 